The subject of the present invention is a synergistic fungicidal composition comprising propamocarb and a derivative of phosphorous acid and a process which makes use of the said composition and which is intended for the curative or preventive protection of crops against fungal attacks.
It is always desirable to improve the spectrum of activity and the effectiveness of such compounds with a fungicidal effect or to reinforce them by combining them with other molecules in order to obtain a more effective product (combination with a systemic fungicide, these fungicides instead being molecules of xe2x80x9ccontactxe2x80x9d type) or alternatively to prevent the appearance of fungal strains which are resistant to these new fungicides.
It is also highly desirable to have available fungicidal products which enjoy an improved persistance of effect, likely to space out in time the number of plant-protection treatments necessary for satisfactory control of the parasites.
It is, in any event, particularly advantageous to be able to decrease the amount of chemicals distributed in the environment, while ensuring high-performance protection of crops against fungal attacks.
It has now been found that one (or a number) of the above objectives could be achieved by virtue of the fungicidal composition according to the present invention.
The subject of the present invention is therefore, in first place, a synergistic fungicidal composition comprising, as compound A, propamocarb, also known as propyl 3-(dimethylamino)propylcarbamate, and at least one fungicidal compound B chosen from the group comprising derivatives of phosphorous acid, for example metal phosphites, such as fosetyl-Al, and phosphorous acid itself and its alkali metal or alkaline earth metal salts.
The fungicidal composition according to the invention advantageously comprises the components A and B in an A/B ratio by weight of between 1/12 and 12/1, is preferably between 1/3 and 3/1, and more advantageously still in a ratio equal to 1.
It is clearly understood that the said fungicidal composition can contain a single compound B or more than one such compound, for example 1, 2 or 3 compounds B, according to the use for which the composition is intended.
Preference is further given, among the more especially preferred meanings of the compound B defined above, to fosetyl-Al. The composition is preferably not applied on lawns. In an entirely unexpected way, the composition according to the invention then significantly improves the effect of the active materials taken separately with respect to a number of fungi which are particularly harmful to crops, for example in particular grapes or the Solanaceae. This improvement is reflected in particular by a decrease in the doses of each of the constituents, which is particularly advantageous for the user and the environment. The fungicidal product thus exhibits synergic properties attested by application of the Tammes method, xe2x80x9cIsoboles, a graphic representation of synergism in pesticidesxe2x80x9d, Netherlands Journal of Plant Pathology, 70(1964), pp. 73-80.
Preferably, when the component B is fosetyl-Al, the A/B ratio is between 1/3 and 3/1, and, more advantageously still, this ratio is equal to 1, for all the crops envisaged.
The structures corresponding to the common names of the active materials A and B are shown in at least one of the following 2 works:
xe2x80x9cThe Pesticide Manualxe2x80x9d, edited by Clive Tomlin and published by The British Crop Protection Council, 10th edition (pages 843 and 530);
l""Index phytosanitaire [Plant-protection index] 1994, published by l""Association de Coordination Technique Agricole [Agricultural Technical Coordination Association], 30th edition.
The fungicidal composition according to the invention comprises, as active material, a compound A and at least one compound B as a mixture with solid or liquid vehicles which are acceptable in agriculture and/or surface-active agents which are also acceptable in agriculture. In particular, the inert and conventional vehicles and the conventional surface-active agents can be used. These compositions cover not only compositions which are ready to be applied to the crop to be treated by means of a suitable device, such as a spray device, but also commercial concentrated compositions which have to be diluted before application to the crop. The combination of at least one compound A with at least one compound B is denoted as active material.
These compositions can also contain any kind of other ingredients such as, for example, protective colloids, adhesives, thickening agents, thixotropic agents, penetrating agents, stabilizing agents, sequestering agents and the like. More generally, the compounds A and B can be combined with all the solid or liquid additives corresponding to the conventional formulating techniques.
Generally, the compositions according to the invention usually contain from 0.05 to 95% (by weight) of active material, one or more solid or liquid vehicles and, optionally, one or more surface-active agents.
In the present account, the term xe2x80x9cvehiclexe2x80x9d denotes a natural or synthetic, organic or inorganic material with which the active material is combined to facilitate its application on the aerial parts of the plant. This vehicle is thus generally inert and it must be acceptable in agriculture, especially on the treated plant. The vehicle can be solid (clays, natural or synthetic silicates, silica, resins, waxes, solid fertilizers and the like) or liquid (water, alcohols, especially butanol, and the like).
The surface-active agent can be an emulsifying, dispersing or wetting agent of ionic or nonionic type or a mixture of such surface-active agents. There may be mentioned, for example, salts of polyacrylic acids, salts of lignosulphonic acids, salts of phenolsulphonic or naphthalenesulphonic acids, polycondensates of ethylene oxide with fatty alcohols or with fatty acids or with fatty amines, substituted phenols, (especially alkylphenols or arylphenols), salts of esters of sulphosuccinic acids, taurine derivatives (especially alkyltaurates), phosphoric esters of polyoxyethylenated phenols or alcohols, esters of fatty acids and of polyols, and the derivatives of the above compounds containing sulphate, sulphonate and phosphate functional groups. The presence of at least one surface-active agent is generally indispensable when the active material and/or the inert vehicle is/are not soluble in water and the carrier agent for application is water.
The compositions for agricultural use according to the invention can thus contain the active material within very wide limits, ranging from 0.05% to 95% (by weight). Their surface-active agent content is advantageously between 5% and 40% by weight. Except when otherwise indicated, the percentages given in this description, including the claims, are by weight.
These compositions according to the invention are themselves in fairly diverse, solid or liquid forms.
There may be mentioned, as forms of solid compositions, the powders for dusting (with an active material content which can range up to 100%) and the granules, especially those obtained by extrusion, by compacting, by impregnation of a granulated support, or by granulation from a powder (the active material content in these granules being between 0.5 and 80% for the latter cases), the tablets or effervescent tablets.
The fungicidal composition according to the invention can also be used in the form of powders for dusting; it is also possible to use a composition comprising 50 g of active material and 950 g of talc; it is also possible to use a composition comprising 20 g of active material, 10 g of finely divided silica and 970 g of talc; these constituents are mixed and milled and the mixture is applied by dusting.
There may be mentioned, as forms of liquid compositions or those intended to constitute liquid compositions at the time of application, solutions, in particular water-soluble concentrates, emulsions, suspension concentrates, aerosols, wettable powders (or powder to be sprayed), pastes or gels.
The suspension concentrates, which can be applied by spraying, are prepared so as to obtain a stable fluid product which does not settle out and they generally contain from 10 to 75% of active material, from 0.5 to 15% of surface-active agents, from 0.1 to 10% of thixotropic agents and from 0 to 10% of suitable additives, such as antifoaming agents, corrosion inhibitors, stabilizing agents, penetrating agents and adhesives and, as vehicle, water or an organic liquid in which the active material is insoluble or nearly insoluble: certain organic solid materials or inorganic salts can be dissolved in the vehicle to aid in preventing sedimentation or as antigels for water.